Metal ion binding monomer and polymer

ABSTRACT

The present invention relates to bis-imidazolyl compounds of the formula:  &lt;IMAGE&gt;  and polymers having the above-identified bis-imidazolyl compounds as a polymerizable unit. The present invention further relates to a method for scavenging trace quantities of metal ions from various effluents sources using the polymers of the instant invention. The instant invention also is directed to the use of the above-identified polymers as corrosion inhibiting agents and as a film for use in gel electrophoresis.

FIELD OF THE INVENTION

The present invention relates to novel bis-imidazolyl compounds and to polymers which contain the novel bis-imidazolyl moieties therein as a polymerizable unit. The present invention further relates to the use of these polymers for water treatment, preservation of machine oils, films for gel electrophoresis, packing materials for columns and for protective coatings for various metal surfaces. The instant invention also relates to a kit which comprises a filter having the polymers of the present invention therein.

BACKGROUND OF THE INVENTION

Those skilled in the art are well aware of the technological importance of chelating agents for removing metal ions from various effluents, such as waste water, plating baths and the like. Chelating agents provide means of manipulating and controlling metal ions by forming complexes that usually have properties that are markedly different from those of the original metal ions or the chelators. These properties may serve to reduce undesirable effects of metal ions in drinking water, waste water, sewage and the like. Thus, new and improved chelating agents are continuously being developed which have a high selectivity and capacity for binding various metal ions.

An important class of chelating agents are those which are derived from a bis-imidazolyl moiety. These compounds have shown an excellent ability to bind various metal ions, especially Cu²⁺, effectively due to the proximity of the lone electron pairs on each of the nitrogen atoms in the imidazolyl rings.

Extensive studies of various bis-imidazolyl compounds have been conducted in recent years to determine the binding characteristics of these compounds, See, for example Drey, et al. "Metal Chelates of Bis-Imidazole," Biochemistry, Vol. 4, No. 7, pp. 1258-1263, July 1965 and Breslow, et al., "Models or Metal Binding Sites in Zinc Enzymes. Synthesis of Tris [4(s)-imidazolyl]carbinol (4-TIC), Tris (2-imidazolyl)carbinol (2-TIC), and Related Ligands, and Studies on Metal Complex Binding Constants and Spectrum," JACS, Vol. 100, No. 12, pp. 3918-3922, June 1978.

A specific bis-imidazolyl compound that has been developed in recent years is disclosed in U.S. Pat. No. 4,869,838 to Gorun et al. More specifically, the reference discloses a bis-imidazole ether of the following formula: ##STR2## wherein R is a normal alkyl group having from 1 to 12 carbon atoms and R' is a normal alkyl group having from 7 to 12 carbon atoms, an alkylaryl group having from 7 to 20 carbon atoms, or an aryl group of 6 to 10 carbon atoms. The above-identified bis-imidazolyl ether compounds are useful for complexing metal ions which are present in lubricating oils.

Despite the current state of the art, there is still a need for developing new metal chelators that have the ability to selectively and reversible bind metal ions. Additionally, due to the growing awareness of the environment in recent years, there is a continual need for developing new metal chelators that have the capacity for binding large quantities of trace amounts of metal ions from various effluent streams.

SUMMARY OF THE INVENTION

The present invention is directed to novel bis-imidazolyl compounds of the formula: ##STR3## wherein R¹ is hydrogen, lower alkyl, lower alkenyl, lower alkynyl or lower alkoxy; R² is lower alkoxy or hydroxy; and R³ is lower alkyl or a substituted or aryl containing 6 to 10 ring carbon atoms wherein the substituents on the ring carbon atoms are independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, sulfate, nitro, lower alkanoyl or formyl; or R² and R³ taken together form --═CR⁴ R⁵ -- wherein R⁴ and R⁵ are the same or different and are lower alkyl.

The present invention also relates to polymers which comprise the polymerizable unit of the following formula: ##STR4## wherein R¹ is hydrogen, lower alkyl, lower alkenyl, lower alkynyl or lower alkoxy; R² is lower alkoxy or hydroxy; R³ is lower alkylene or a substituted arylene containing 6 to 10 ring carbon atoms wherein the substituents thereon are independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, sulfate, nitro, lower alkanoyl or formyl.

The foregoing polymerizable unit may also be combined with other polymerizable units to form novel copolymers, block copolymers, latex polymers, thermoplastic polymers, and the like.

Also, the present invention relates to a method for removing trace quantities of heavy metal ions from various waste water effluents using the aforementioned polymers and to a kit that contains a filter having the novel bis-imidazolyl polymers therein.

The present invention is further directed to the use of the novel polymers as a corrosion inhibiting agent, a column packing material and a film for use in gel electrophoresis.

DETAILED DESCRIPTION OF THE INVENTION

As described hereinabove, the present invention encompasses bis-imidazolyl compounds of the formula: ##STR5## wherein R¹, R² and R³ are as defined hereinabove.

The alkyl groups when used alone or in combination with other groups, are lower alkyls containing from 1 to 6 carbon atoms and may be straight chained or branched. These groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, and the like.

As used herein, the term "lower alkoxy" refers to --O-- alkyl groups, wherein the alkyl is defined hereinabove. The alkoxy group may be straight chained or branched; although the straight-chain is preferred. Examples include methoxy, ethyloxy, propoxy, butyloxy, t-butyloxy, i-butyloxy, i-propoxy, and the like.

The term lower alkenyl is an alkenyl group containing from 2 to 6 carbon atoms and at least one double bond. These groups may be straight chained or branched and may be in the Z or M form. Such groups include vinyl, propenyl, 1-butenyl, isobutenyl, 2-butenyl, 1-pentenyl, (Z)-2-pentenyl, (E)-2-pentenyl, (Z)-4-methyl-2-pentenyl, (E)-4-methyl-2-pentenyl, pentadienyl, e.g. 1,3 or 2,4-pentadienyl, and the like.

The term alkynyl includes alkynyl substituents containing 2 to 6 carbon atoms and may be straight chained as well as branched. It includes such groups as ethynyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl, 3-methyl-1-pentynyl, 3-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, and the like.

The term lower alkanoyl as used herein means an alkyl group containing 1 to 6 carbon atoms which contains an oxo substituent therein. Preferred alkanoyls are those wherein the --C═O-- group is attached directly to the aryl group. Such groups include ethanoyl, propanoyl, butanoyl, and the like.

The term halogen includes fluoro, chloro, bromo, iodo and the like.

The term aryl, when used alone or in combination, refers to an aromatic group which contains from 6 up to 10 ring carbon atoms. The aryl groups are monocyclic compounds that may be substituted or unsubstituted. If substituted, the substituents on the ring carbon atoms may be independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, sulfate, nitro, lower alkanoyl or formyl. The aryl groups include phenyl, α or β naphthyl, and the like. The aryl group may be mono, di or trisubstituted. It is preferred that the aryl group is at least monosubstituted.

The preferred values of R¹ are hydrogen and especially lower alkyl containing from 1 to 3 carbon atoms. The most preferred value of R¹ is methyl.

The preferred values of R² are hydroxy or methoxy, with hydroxy being especially preferred.

The preferred values of R³ are a lower alkyl or a substituted or unsubstituted aryl. When R³ is lower alkyl it is preferred that the lower alkyl contain from 1 to 3 carbon atoms. The most preferred lower alkyl is methyl. When R³ is a substituted aryl it is preferred that the substituted aryl be phenyl. It is especially preferred that R³ be styryl.

When R² and R³ form --═CR⁴ R⁵ -- it is preferred that at least one of R⁴ and R⁵ is methyl. It is most preferred that both R⁴ and R⁵ be methyl.

A preferred class of bis-imidazolyl compounds are represented by the following formula: ##STR6## wherein R³ is a lower alkyl or a substituted aryl compound. When R³ is lower alkyl, it is preferred that the lower alkyl contains from 1 to 3 carbon atoms. The most preferred lower alkyl is methyl. When R³ is a substituted aryl it is preferred that the substituted aryl be phenyl and that it be monosubstituted. It is especially preferred that R³ be styryl.

Another preferred class of bis-imidazolyl compounds are those that are represented by the following formula: ##STR7##

wherein R² and R³ taken together form --═CR⁴ R⁵ -- wherein R⁴ and R⁵ are the same or different and are lower alkyl.

The most preferred bis-imidazolyl compounds encompassed by Formula I are those wherein:

R¹ is methyl, R² hydroxy and R³ is methyl;

R¹ is methyl, R² hydroxy and R³ is styryl;

R¹ is methyl, R² methoxy and R³ is styryl;

The present invention further relates to polymers which comprise the polymerizable unit of the following formula II: ##STR8## wherein the variables R¹ and R² have the above-identified meaning and R³ is lower alkylene or a substituted arylene containing from 6 to 10 ring carbon atoms wherein the substituents on the ring carbon atoms are independently hydrogen, lower alkyl, lower alkanoyl, lower alkenyl, lower alkoxy, halogen, sulfate, nitro, or formyl. As used herein, the arylene group is an aryl group which is substituted to the polymeric chain in two positions, i.e. --Ar--. It is preferred that the arylene group is monosubstituted, but the arylene may be mono-, di- or tri-substituted. As used herein the term "styrylene" refers to the phenylethylene unit. Unless indicated to the contrary, the term polymerizable "unit" refers to the above structural unit of the polymer.

Homopolymers of the present invention are compounds of the formula ##STR9## wherein R₁, R₂ and R₃ are as defined hereinabove and n is an integer from 2 to 100,000. Preferred values of n are between about 50 to about 1000. The most preferred values of n range from about 100 to about 500.

The preferred R³ are ##STR10## or (CH₂)_(x) wherein x is an integer from 2 to 6. Especially preferred values of x are from 2 to 4.

It should be noted that the polymers of the present invention may be homopolymers as described hereinabove containing only repeating bis-imidazolyl monomeric units. Alternatively, they can be copolymers, block copolymers, latex polymers, thermoplastic polymers, and the like. That is, the polymerizable units of the present invention described hereinabove may be polymerized with other polymerizable monomers that are presently available to form copolymers, block copolymers, latex polymers and thermoplastic. Suitable polymerizable monomers that can be polymerized with the identified polymerizable units of Formula II include lower alkene units or arylalkene units, such as ethylene, propylene, 1-butylene, styrene, and the like.

The preferred values of R¹ and R² for the polymerizable units of the present invention are the same as those mentioned hereinabove regarding the bis-imidazolyl compounds. For example, the preferred values of R¹ are hydrogen or lower alkyl containing from 1 to 3 carbon atoms. The most preferred value of R¹ is methyl. The preferred values of R² are hydroxy or methoxy, with hydroxy being especially preferred.

The preferred values of R³ of the polymerizable units of the present invention are those wherein R³ is a lower alkylene or a substituted arylene. When R³ is lower alkylene, it is preferred that the lower alkylene contain from 1 to 3 carbon atoms. The most preferred lower alkylene is methylene. When R³ is a substituted arylene, it is preferred that the arylene be a mono- or disubstituted phenylene. It is especially preferred that R³ be styrylene. The most preferred polymers of the present invention are those wherein the polymers have the following formula: ##STR11## wherein n is an integer ranging from about 2 to about 100,000. Preferred values of n are between about 50 to about 1000. The most preferred values of n range from about 100 to about 500. This particular embodiment is directed to polymers that contain repeating units of a bis-methylimidazolyl styrenyl compound. That is, the formula shown hereinabove relates to homopolymers containing only the bis-methylimidazolyl styrenyl monomeric unit.

Another preferred polymer of the present invention is represented by the following formula: ##STR12## wherein n is an integer ranging from about 2 to about 100,000. Especially preferred values of n are from 500 to about 2000. Most preferably, n is from about 1000 to about 1500. The above formula represents a poly(bis-methylimidazolyl) polymer.

The following scheme of preparation is generally exemplary of the process which can be employed in the preparation of bis-imidazolyl compounds of Formula I of the instant invention. Although the compounds in the reaction scheme are specific-for values of R¹ being methyl, R² being hydroxy and R³ being styryl, it is just as applicable to compounds that have different values of R¹, R² and R³ as defined hereinabove. ##STR13##

Scheme I outlines a general methodology for reacting an acylating intermediate, such as an ester or acid chloride, with an imidazole anion to form the product of Formula I. However, Scheme I shows two alternative methods for preparing bis-imidazolyl compounds of the present invention.

In one method, as shown in the top portion of this reaction scheme, 4-vinylbenzoic acid (1) is esterified by techniques known to one skilled in the art. For instance, compound 1 is reacted with a base, e.g. sodium ethoxide, in an organic solvent which is non-reactive with the reagents and in which 1 and the reactants are soluble, such as dimethyl formamide (DMF). This particular reaction step serves to remove a hydrogen from compound 1 to create a sodium salt, 2. This sodium salt compound is then combined with iodomethane (CH₃ I) in DMF solvent under heat and a nitrogen atmosphere to form the ester intermediate, 3. An imidazole anion methylimidazole anion, 4, is then prepared by dissolving a suitable quantity of the imidazole in a suitable solvent, e.g. tetrahydrofuran (THF), at low temperatures, e.g. -78° C. in a dry ice/ethanol bath. A strong base capable of removing a hydrogen from the imidazole, such as n-butyllithium (n-BuLi), is reacted with the imidazole at cold temperatures, e.g. -78° C. or lower, and this product is then reacted with the acylating intermediate to form the product of Scheme I (5).

In the alternative route of this reaction scheme which is illustrated in the lower portion of Scheme I, vinylbenzoic acid 1 is reacted with thionyl chloride (SOCl₂) to create the acid chloride intermediate, 6. The acid chloride intermediate thus formed is then added to a solution of 4 and n-BuLi in the same manner as mentioned hereinabove.

It should be noted that the process illustrated in the lower half of this reaction scheme is the preferred method of making the bis-imidazolyl compounds of the present invention since it involves one less reaction step and that acid chloride intermediates produced by this route are generally more reactive than their ester counterparts.

Polymerization of the polymerizable unit is done under polymerization conditions, e.g., free radical generation. Effective amounts of free radical initiators effective to form free radical intermediates are utilized. These may be commercially available or prepared in situ. For example, organic peroxides, such as bi(lower)alkanoyl peroxides, aryloyl lower alkanoyl peroxides, biarylyl alkanoyl, e.g., benzoyl peroxide, AIBN or the like may be employed by the present invention. Alternatively, UV light may be used to generate free radicals. In fact, UV light and organic peroxide may be used in combination.

Different approaches can be taken in synthesizing the bis-imidazolyl polymers of the present invention and these various techniques are known to one skilled in the art. For instance, a bis-imidazolyl compound of Formula I is dissolved in a suitable polymerizable compound in appropriate weight percent ratios and then polymerized. Suitable polymerizable compounds include lower alkene, or arylalkene, e.g., ethylene, propylene, 1-butylene, styrene/divinylbenzene, lower alkylene oxy carbonyl-lower alkene, lower alkylene oxy carbonyl lower arylalkene, such as ethylene glycol dimethacrylate (EGDMA), lower alkanols, such as methanol, and the like. These polymerizable compounds are used in the present invention as backbones to which the functionalized imidazolyl compounds are directly bound to. The weight % ratio of the bis-imidazolyl compound to polymerizable compounds may vary over a wide range depending on the type of polymer being produced.

Typically, the weight % ratio of bis-imidazolyl compound to these polymerizable compounds varies from about 1 to about 100. Preferably, this weight % ratio of bis-imidazolyl compound to these polymerizable compound is from about 10 to about 90. The most preferred weight % ratio is from 40 to about 80.

Polymerization of the dissolved solution is performed by art-recognized techniques. For example, polymerization is initiated by adding an organic peroxide, such as benzoyl peroxide, or azodiisobupyronitrile (AIBN) derivative and then heating or exposing the solution to ultraviolet light.

The amount of the organic peroxide compound or AIBN derivative that is employed in the present invention is from about 0.5 to about 10 weight %. More preferably, the amount of organic peroxide compound or AIBN derivative that is needed to initiate the polymerization is from about 0.5 to about 2 weight %.

Another process for preparing the polymers of the present invention is shown in reaction Scheme II. ##STR14##

Two imidazole anions, generated as described hereinabove, react with a polymerizable compound, such as PMMA, to generate the product. Without wishing to be bound, it is believed that a methylimidazolyl anion, which is generated in-situ by reacting 1-methylimidazole with n-BuLi, undergoes a nucleophilic substitution reaction with the ester moiety of poly(methylmethacrylate) (PMMA) to form a ketone intermediate. This intermediate is then subsequently attacked by another methylimidazolyl anion to form a bis-methyimidazolyl alkoxy anion (this particularly species is not shown in the foregoing reaction scheme). This species is then quenched with a suitable quenching agent, such as water, to form the poly(bis-methylimidazolyl) polymer.

The present invention is further directed to a method for scavenging or removing heavy metal ions from various effluents that contain these ions. The term heavy metal ions as used herein connotates any metal that is heavier than calcium. The heavy metal ions also include such metals as aluminum and the lanthanide and actinide elements. It is most preferred that the metal ions be iron, copper, lead, mercury, cobalt, plutonium, thorium, zinc, and the like. Especially preferred metal ions include Fe²⁺, Cu²⁺, Pb²⁺, Hg²⁺, Co²⁺, Zn²⁺, Fe³⁺, Pu⁴⁺ and Th³⁺. The most especially preferred metals include Cu²⁺ and Pb²⁺. The polymers of the present invention have a high affinity for chelating heavy metals, as defined herein, especially Cu²⁺ and Pb²⁺. By high affinity, it is meant that the polymers are able to remove very small amounts, in the ppb levels, of these ions from the effluent.

The polymers of the instant invention also exhibit a high capacity for binding heavy metals, such as Cu²⁺ and Pb²⁺ ions, even when these ions are present at extremely low concentration levels in a sample. For example, in the case of Cu²⁺, the polymers of the instant invention exhibit a capacity which is greater than 5 meq/g. In another example, the polymers of the instant invention have a capacity for binding Pb²⁺ that is greater than 3.9 meq/g. This represents an improvement over commercially available polymers or ion exchange resins that are currently employed in the art for removing heavy metal ions from waste water streams. Typically, the commercially available polymers provide chelating capacities near 1-2 meq/g for Cu²⁺ and 0.5 meq/g for Pb²⁺.

The specific method of the present invention for removing heavy metal ions from effluent streams involves first packing a column with a polymer having a polymerizable unit as defined hereinabove in Formula II. The column may be packed by conventional methods that are well known in the art. For instance, a suitable inert material, such as glass wool, is placed in the bottom of the column and then the polymer is poured into the column to form a resin bed. It is especially preferred that the polymers be made into resins or be finely crushed before it is poured into the column. Alternatively, the polymers can be processed into beads, fibers or films. These processes are well known in the art. After packing the column with the polymer, an inert material, such as sand or glass wool, is then placed on the top of the resin bed.

A portion of a waste water effluent is then added to the top of the polymer packed column and the sample is then allowed to elute through the polymer bed. Thereafter, the effluent is then collected at the bottom of the column in a suitable container.

The eluted sample is then analyzed for heavy metal ions, such as Cu²⁺ and Pb²⁺, using well known techniques in the art. For example, the samples may be analyzed by using Chemiluminescence, Gas Chromatography (GC), High Performance Liquid Chromatograph (HPLC), Atomic Absorption, Voltammetry, and the like. In the present invention Voltammetry is the preferred mode for analyzing the samples.

As mentioned hereinabove, the polymers of the present invention exhibit a high affinity as well as a high capacity for removing heavy metal ions. The capacity of the polymers of the present invention for binding heavy metal ions is higher than those previously reported using prior art polymer resins.

The present invention also provides a kit for removing heavy metals from various effluents, as described hereinabove. These metals can be present in the effluent at various concentrations including trace amounts, i.e., even as lower ppb levels. More specifically, the kit of the present invention comprises a filter which contains the novel polymers having the above-identified polymerizable unit therein. More specifically, the filter of the present invention comprises a disposable cartridge which contains the polymers of the present invention. The disposable cartridge employed by the filter of the instant invention could be in the form of a pleated cylinder, flat disc, hollow disc, and the like depending on the specific use of the filter. For example, if the filter is being used for purifying drinking water, the cartridge containing the polymer would typically be in the form of a pleated cylinder having pore sizes ranging from 0.01 to about 50 μm.

In another embodiment, the polymers of the present invention may be also used as a packing material for columns that are used in various analytic instruments, such as HPLC, GC, GC-MS, GLC, and the like. Columns comprising the polymers of the present invention would be especially useful for detecting heavy metal ions as defined herein, since the polymers exhibit a high affinity for such metal ions. Moreover, columns packed with the polymers of the present invention would be able to detect very low levels, i.e., ppb range, of these ions in a sample.

In this embodiment, the polymers would be finely grounded, processed into beads, fibers or films using techniques known to one skilled in the art and mixed with other commercially available packing materials such as silicon, alumina, and the like. The column would then be packed using common techniques that are well known and described in the art.

The polymers of the present invention may also be used as a film for gel electrophoresis. In this particular embodiment, the polymers are made into a thin film which may be used in gel electrophoresis for separating compounds that contain metal ions therein. Furthermore, the polymeric films of the present invention may also be mixed with commonly employed electrophoresis gels, such as starch gel, agar gel or polyacrylamide gel. By this technique, metal containing compounds can be separated from non-metal containing compounds, e.g. proteins can be separated from non-metal containing compounds. In addition, using the polymers of the present invention, various metal containing compounds can be separated from each other. Thus, for example, different proteins can be separated from each other by electrophoresis in which the electrophoresis gel is comprised of polymers of the present invention.

The polymer films for use in gel electrophoresis may be prepared by techniques well known in the art for making such a gel. For example, a finely ground or crushed form, or beaded form, or fiber, of the polymer can be made into a film by exposing it to heat or by treating it with a suitable solvent which would effectively dissolve the polymer. In the liquid state, the polymer could then be placed between two glass plates and then cooled to form a film for electrophoresis.

Alternately, the bis-imidazolyl compounds of the present invention may also be incorporated into a gel. In this embodiment, a bis-imidazolyl compound according to Formula I is polymerized with acrylamide to form a polymer which can be used in gel electrophoresis.

The polymers of the present invention are also corrosion-inhibiting agents. More specifically, the polymers of the present invention are used in inhibiting the corrosion of metals, particularly iron, steel, and ferrous alloys. The polymers of the present invention are employed for inhibiting corrosion in processes which require this protective or passivating coating. They can be used in preventing atmospheric corrosion, underwater corrosion, corrosion in streams, corrosion in chemical industries and underground corrosion.

The corrosion inhibitors contemplated herein find special utility in the prevention of corrosion of pipes or equipment which is susceptible to corrosion. In this embodiment, the polymers may be directly applied onto the metal surface as is, or as a solution in some carrier liquid, paste or emulsion. The polymers of the present invention may also be combined with the polymerizable corrosion inhibiting agents. For instance, the polymers may be applied as a latex paint to the surface of the metal or metal alloy. The latex paint containing the instant polymers of the present invention can be prepared using techniques well known in the art.

For a better understanding of the present invention together with other and further objects, reference is made to the examples.

EXAMPLE 1

Preparation of Poly(bis-methyl imidazolyl) Polymer

Poly(methylmethacrylate) (PMMA) was sifted through a wire mesh with about 1 mm×1 mm holes to remove the larger chunks of PMMA. 9.85 g (98.4 mmol of ester units) of the sifted polymer was then weighed. Tetrahydrofuran was then distilled to remove unwanted impurities from the solvent and two long needles were removed from the 110° C. drying oven and placed in the dry box to cool.

A 500 ml, 3-necked round bottom was flame dried and a stir bar was quickly added. The two outside necks were quickly capped with septa and the middle neck was capped with a powder addition funnel and 14/24 adapter. The powder addition funnel was carefully flame dried and then capped with two septa. The apparatus was flushed with N₂. Thereafter, the sifted PMMA was quickly added to the addition funnel after it had cooled. The apparatus was flushed with N₂ again and then kept under N₂ pressure. 16.16 g (196.8 mmol) of 1-methylimidazolyl (MeIm), about 2 times the molar amount of the ester units in the PMMA, was added to the round bottom flask through one of the septa. Dry THF (120 ml) from the still was added via a dry needle and dry gas-tight syringe. The methylimldazolyl solution was then cooled in a dry ice/EtOH bath with stirring continuing throughout the cooling process.

79 ml (198 mmol) of 2.5M n-butyl lithium in hexane, an equimolar amount to that of the MeIm, was slowly added to the round bottom via a dry gas-tight syringe. This solution was then stirred for about 1 hour in a dry ice bath.

After a period of time, PMMA was added to the MeIm/BuLi solution with the addition funnel. Thereafter, the reaction mixture was stirred vigorously and allowed to thaw to room temperature over 72 hours.

The foregoing reaction mixture war then quenched by adding 5 ml of water. The contents of the flask, a yellow cloudy suspension over a mass of white-yellow gummy solid, were then emptied into a 1 L beaker. 250 ml of THF was then added to the beaker and the content was stirred vigorously for 15 min. The stirring was then stopped and the insoluble solid was left to settle for 10 min. The supernatant was then decanted off. The above separation procedure was repeated with 200 ml of acetone and then 150 ml of THF. The third time, the material was filtered through a large Buchner funnel. This material was allowed to dry over vacuum. It was then crushed with a mortar and pestil and then washed for 15 min in 150 ml of hot water. The material was again filtered with a buchner funnel and dried over vacuum to obtain 3.58 g of a white powder.

EXAMPLE 2

Preparation of Poly(bis-methylimidazolyl) Polymer

The polymer was prepared in the same manner as Example 1 except that anhydrous ether was used instead of THF as the reaction solvent. Also, after quenching with water, the product was washed once in a large portion of boiling water and then filtered with a scintered glass funnel to obtain white or clear small granules of the solid polymer.

EXAMPLE 3

Preparation of Poly(bis-methylimidazolyl Styrenyl)

A small quantity of bis-methylimidazolyl styrene (0.02 g) compound and 0.80 g of 60/40 v/v styrene/DVB solution were placed in a small test tube. A very small magnetic stir bar was added to the test tube, and the mixture was then place in a 60° C. oil bath with stirring. One drop of methanol was then added to help dissolve the bis-imidazolyl. 0.005 g (0.5% w/w of the total polymer mass) of VA 061 radical initiator was added to the test tube. Stirring was continued until all materials were dissolved. The stir bar was then removed and the test tube was capped with a septa. This solution was polymerized by placing it in front of a strong UV light source overnight. After polymerization was complete, the test tube was shattered and the polymer removed. It was then crushed with a mortar and pestil into a powder and this powder was washed with MeOH and filtered and dried over vacuum in a scintered glass funnel to make the 20% w/w polymer.

EXAMPLE 4

50% polymer was synthesized using the same procedure as described in Example 3, except that 0.50 g of bis-methylimidazolyl styrene compound and 0.50 g of styrene/DVB solution were used.

EXAMPLE 5

A 100% polymer was synthesized by placing 102 mg of bis-methylimidazolyl styrene compound and 1 mg of VA 061 initiator into a small test tube. A small stir bar and 0.1 ml MeOH were then added to this tube. The mixture was then put in an oil bath at 70° C. After all of the bis-methylimidazolyl styrene compound had dissolved, the stir bar was removed and the solution was kept in the 70° C. bath overnight to polymerize. The polymerized material was collected and crushed in the manner stated above. It was not washed, as the material was soluble in MeOH.

EXAMPLE 6

A polymer was prepared in accordance with Example 1 except that polymerization was initiated by letting the solution set in the 60° C. oil bath over night.

EXAMPLE 7

This polymer was made in the same manner as Example 3 except that ethylene glycol dimethacrylate (EGDMA) was used as a polymer matrix in place of styrene/DVB.

EXAMPLE 8

Bis-methylimidazolyl (508 mg) was placed in 2.00 g of EGDMA in a erlenmeyer flask. This mixture was then heated in a sand bath. 0.173 g (about a 1/2 molar equivalent of 5) of Cu(OAc)₂.H₂ O was added to the solution. One ml of methanol was then added to the flask. This mixture was heated some more and then passed through a Hirsch funnel. It was then transferred to a test tube and 9.5 mg of VA 061 radical initiator was added and dissolved. The mixture was then put into a 60° C. oil bath and allowed to polymerize over the weekend. The polymer was then crushed and washed as above to produce a dark blue coarse powder. The powder was then washed in about 5 ml of 6M HCl until no more color could be removed. It was then washed in 5% NaOH solution, at which point the material had a green-yellow tint to it.

EXAMPLE 9

The present example determines the metal ion binding capacity of some of the preferred polymers of the present invention. More specifically, the metal ion binding capacity of polymer produced in Examples 1 and 3 and 7 were determined. The specific metal ions analyzed in this investigation were Cu²⁺, Pb²⁺, Fe²⁺, Fe²⁺ and Hg²⁺. Additionally, the binding capacity of these polymers for Cu²⁺ in the presence of excess amounts of Cu²⁺ and Mg²⁺ were also determined.

The following two analytic procedures were employed in the present invention to analysis the foregoing metal ions.

Analysis of Polymer Prepared by Example 1

Apparatus: A 3-electrode system with a glassy carbon, rotated disk working electrode was constructed in the lab. It was controlled by a 1/40 horsepower G. K. Heller motor and a Series H motor controller (G. K. Heller Corp., Floral Park, N.Y.) with an external voltage control input. The rotation rate was related to the voltage applied to the control input. This allowed us to switch between two independently selected voltages to obtain two reproducible rotation rates.

A separate voltage was applied to the electrochemical cell. This voltage was applied to the working electrode using a BAS (Bioanalytical Systems, Inc.) CV-27 Cyclic Voltammograph. Current output was plotted using a BAS X-Y-Recorder.

The polymer was finely crushed and placed in the tube between two 0.5 micron filters.

Electrodes: The working electrode was a glassy Carbon 3 mm disk which was polished with successively finer polishing paper and finally a 1 micron alumina slurry. The reference electrode was a chloridized silver wire in 3M NaCl. The auxiliary electrode was a polished platinum wire.

Reagents: Deionized water from a Milli-Q system was used to prepare all solutions. A stock 10⁻³ M Cu²⁺ solution was made by dissolving clean copper metal in 1.0 mL 15M HCl and diluting to 1.0 L. This was used for all Cu²⁺ solutions and diluted to lower concentrations for daily use. Reagent grade HCl was used as supporting electrolyte.

Procedure: A 10.0 mL aliquot of 0.1M HCl was placed under the electrode, and pretreatment begun. Pretreatment involved cycling from +1.0 V to -1.0 V twice and holding at each voltage for 10 minutes. Oxygen was purged by placing one nitrogen tube so it bubbled through the solution while a second nitrogen tube remained above the surface to blanket the liquid. After pretreatment and between each run, the electrodes were rinsed with deionized water and dried with a chim-wipe. Each solution was derated for ten minutes before analysis began.

Aliquots of 10.0 mL of Cu²⁺ were pipetted into the centrifuge tube and forced through the flow-cell under pressure. Each aliquot was collected in a plastic weighing bottle. 333 microliters of 3M HCl was added to each aliquot to bring the supporting electrolyte concentration to 0.1 OM HCl.

A preliminary experiment was run to see what the Cu²⁺ should look like once the polymer was no longer removing copper. A 10.0 mL aliquot of 1.0×10⁻⁵ M copper (not exposed to the polymer) was de-aerated. The nitrogen tubes remained in place and a potential of -0.5 V was applied. The rotation rate was switched between preselected slow and fast rates a few times, holding at each rate for approximately 20-30 seconds.

This procedure was repeated with each of the filtrates.

A calibration curve was made following the same basic guidelines. The sample value was compared to this curve and concentration of each filtrate determined. These values were combined to calculate the capacity. (See Table 1).

Analysis of PMMA Polymers

Apparatus: Ultraviolet absorption spectra were obtained using a Hewlett Packard 8452A Diode Array Spectrophotometer. Voltammetric spectra were measured on a BAS 100 W Program with a BAS 100 B controlling module, EG&G Parc Cell Stand. The electrodes are the same as above, a glassy carbon working electrode, an AgCl reference electrode and a platinum wire as an auxiliary electrode.

Reagents: 0.2M Cu²⁺ and 0.2M Fe³⁺ solutions were prepared by dissolving reagent grade metal nitrates in distilled water. 100 mL of the Cu²⁺ solution were removed and appropriate amounts of calcium nitrate and magnesium nitrate added to bring the concentration of each to 0.1M. 3.0 mg/100 mL solution of HgCl₂ was prepared using distilled water. 100 ml of 5% KSCN solution was made up by weighing out 5.02 g of KSCN and added distilled water until it weighed 100 g. 0.02M Pb²⁺ solution was prepared by dissolving Pb metal in concentrated nitric acid and diluting with deionized water.

Procedures:

Cu²⁺ test:

A known amount, typically 1 gm, of polymer was weighed out and placed in a polyethylene weigh bottle with 11.5 mm stir bar. 50 mL of 0.2M Cu²⁺ solution was added and the solution was stirred on a rotating stir plate overnight. Approximately 5 mL of this solution was then removed and passed through a 0.45 micron filter. A plastic 1-cm cuvette was rinsed with some of this solution which was discarded and more solution added. This sample was scanned from 200-820 nm. The peak at 800 nm was recorded. This was compared to a calibration curve made using dilutions of the standard Cu⁺ solution. The capacity was then calculated to the value shown in Table 1.

Cu²⁺ in the presence of Ca²⁺ and Mg²⁺ test:

A known amount, typically 1 gm, of the polymer was weighed out and placed in a polyethylene weigh bottle with a 11.5 mm stir bar. 50 mL of the 0.1M Ca²⁺, 0.1M Mg²⁺ was scanned. Then the sample, filtered as above was scanned. This value was compared to the copper calibration curve and capacity calculated. (See Table 1).

Fe³⁺ test:

A known amount, typically 1 gm, of the polymer was weighed out and placed in a polyethylene weigh bottle with a 11.5 mm stir bar. 50 mL of 0.02M Fe³⁺ was added and the solution stirred overnight on a rotating stir plate. Approximately 5 mL of this solution was then filtered through a 0.45 micron filter. This sample was scanned from 500-800 nm and the absorption at 654 nm was recorded. This value was compared to a calibration curve made up by diluting the standard Fe³⁺ solution and the capacity was calculated. (See Table 1).

Hg²⁺ test:

A known amount, typically 1 gm, of polymer was weighed out into a polyethylene weigh bottle. 50 mL of the mercuric chloride solution were added along with a 11.5 mm stir bar. The solution was stirred on a rotating stir plate overnight. Blank of 40 mL of 5% KSCN solution diluted to 100 mL was scanned. 25 mL of mercuric chloride solution was then filtered and placed in 50 mL volumetric flask. 20 mL of KSCN solution was added and volume brought up to the mark with distilled water. This was placed in a 1 cm quartz cuvetter and scanned. The value at 282 nm was recorded. This was compared to a calibration curve made up by varying the amount of the standard mercuric chloride solution and distilled water while keeping the amount of KSCN constant. From this curve the capacity was calculated. (See Table 1).

Control Test:

A known amount, typically 1 gm, of nonfunctionalized PMMA polymer was weighed out and placed in a polyethylene bottle with a stir bar. 50 mL of the standard Cu²⁺ solution was added and stirred overnight on the rotating stir plate. A small amount of this solution was removed and filtered. It was scanned and the value at 800 nm recorded. This was compared to the calibration curve and showed no copper removal by the nonfunctionalized polymer.

Pb²⁺ test:

A known amount, typically 1 gm, of the polymer was weighed out and placed in a polyethylene weigh bottle with a 11.5 mm stir bar. 50 mL of 0.2M Pb²⁺ was added and the solution stirred overnight on the magnetic stir plate. The sample was passed through 0.45 micron filter. 1 mL of sample was diluted to 100 mL using deionized water in a volumetric flask. The glassy carbon electrode was polished with an alumina suspension and rinsed with deionized water. The dilute sample was purged with nitrogen for ten minutes. It was scanned from -1000 mV to -100 mV on the DPT cycle. The peak at -348 mV was recorded. This was compared to a calibration curve. The values for the curve were found by scanning 5×10⁻⁵ M Pb²⁺ solution prepared from standard after purging for ten minutes. This solution was then spiked for each successive scan and purged for two minutes. The calculated capacity is shown in Table 1.

The results of this experiment are shown in Table 1. The data in this table illustrates that the polymers of the present invention are capable of binding metal ions efficiently. Moreover, the polymer prepared in accordance with the procedure described in Example 1 exhibited an extremely high capacity or binding Cu²⁺, Pb²⁺ and Fe²⁺ ions. This valves report for this example are higher then those previously reported using commercial available ion exchange resins.

                  TABLE 1                                                          ______________________________________                                         Binding Capacity of Different Polymers for                                     Various Metal Ions.                                                            Polymer     Binding Capacity (in meq/g)                                        Description Cu.sup.2+                                                                               Cu.sup.2+ *                                                                             Pb.sup.2+                                                                           Fe.sup.3+                                                                           Hg.sup.2+                              ______________________________________                                         See Example 1                                                                              5.04     --       3.97 5.38 0.055                                  See Example 3                                                                              0.0057   --       --   --   --                                     See Example 1**                                                                            1.44     1.39     1.09 --   --                                     ______________________________________                                          *Denotes that the measurement was conducted in the presence of excess          Ca.sup.2+ and Mg.sup.2+.                                                       **Same procedure as Example I except that the MeIm/BuLi solution was adde      to solid PMMA.                                                           

The above preferred embodiments and examples are given to illustrate the scope and spirit of the present invention. These embodiments and examples will make apparent to those skilled in the art other embodiments and examples. These other embodiments and examples are also within the contemplation of the present invention. Therefore, the present invention would be limited only by the appended claims. 

What is claimed is:
 1. A bis-imidazolyl compound of the formula ##STR15## wherein: R¹ is hydrogen, lower alkyl, lower alkenyl, lower alkynyl or lower alkoxy;R² is lower alkoxy or hydroxy; and R³ is a substituted aryl containing 6 to 10 ring carbon atoms wherein the substituents on the ring carbon atoms are independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, sulfate, nitro, lower alkanoyl or formyl; or R² and R³ taken together form --═CR⁴ R⁵ -- wherein R⁴ or R⁵ are the same or different and are lower alkyl.
 2. The bis-imidazolyl compound according to claim 1 wherein R¹ is hydrogen or lower alkyl.
 3. The bis-imidazolyl compound according to claim 2 wherein R¹ is lower alkyl containing from 1 to 3 carbon atoms.
 4. The bis-imidazolyl compound according to claim 3 wherein the lower alkyl is methyl.
 5. The bis-imidazolyl compound according to claim 1 wherein R² is hydroxy or methoxy.
 6. The bis-imidazolyl compound according to claim 1 wherein R³ is a substituted aryl.
 7. The bis-imidazolyl compound according to claim 6 wherein R³ is a substituted phenyl.
 8. The bis-imidazolyl compound according to claim 7 wherein the phenyl compound is mono- or disubstituted.
 9. The bis-imidazolyl compound according to claim 8 wherein the monosubstituted phenyl is styryl.
 10. The bis-imidazolyl compound according to claim 1 wherein R² and R³ taken together form --═CR⁴ R⁵ -- wherein R⁴ and R⁵ are the same or different and are lower alkyl.
 11. The bis-imidazolyl compound according to claim 10 wherein R⁴ and R⁵ are both methyl.
 12. A compound according to claim 1 wherein R¹ is lower alkyl, R² is hydroxy and R³ is a substituted aryl.
 13. A compound according to claim 12 wherein the lower alkyl is methyl.
 14. A compound according to claim 12 wherein R³ is a substituted phenyl.
 15. A compound according to claim 14 wherein the substituted phenyl is mono- or disubstituted.
 16. A compound according to claim 15 wherein the monosubstituted phenyl is styryl.
 17. A compound according to claim 1 wherein R¹ is lower alkyl and R² and R³ taken together form --═CR⁴ R⁵ -- wherein R⁴ and R⁵ are the same or different and are lower alkyl.
 18. A compound according to claim 17 wherein R⁴ and R⁵ are both methyl. 